Method of expelling liquid propellant from a storage tank in a liquid rocket

ABSTRACT

A bellows of &#39;&#39;&#39;&#39;55-Nitinol&#39;&#39;&#39;&#39; metal within a liquid propellant storage tank in a liquid rocket is used to expel liquid propellant from the storage tank for use in the liquid rocket. The &#39;&#39;&#39;&#39;55-Nitinol&#39;&#39;&#39;&#39; bellows is deformed, while at a temperature below the transition temperature of the &#39;&#39;&#39;&#39;55-Nitinol,&#39;&#39;&#39;&#39; from the fully expel natural and normal position to the position necessary to permit filling of the storage tank with the liquid propellant. After the storage tank has been loaded with the liquid propellant, and when it becomes necessary to use the liquid propellant, the &#39;&#39;&#39;&#39;55-Nitinol&#39;&#39;&#39;&#39; bellows is heated to a temperature above the transition temperature of the &#39;&#39;&#39;&#39;55-Nitinol.&#39;&#39;&#39;&#39; As a result, the &#39;&#39;&#39;&#39;55-Nitinol&#39;&#39;&#39;&#39; bellows returns to the fully expel natural and normal position and, thereby, expels the liquid propellant from the storage tank for use in the liquid rocket.

United States Patent [191 White 1 May 22, E73

[54] METHOD OF EXPELLING LIQUID 3,285,470 3,435,996 4/l969 Jones PROPELLANT FROM A STORAGE TANK IN A LIQUID ROCKET Howard M. White, Philadelphia, Pa.

Assignee: The United States of America as represented by the Secretary of the Air Force, Washington, DC.

Filed: Sept. 23, 1971 Appl. No.: 183,184

Inventor:

References Cited UNITED STATES PATENTS 11/1966 Frei et al. ..222/54 Primary ExaminerStanley H. Tollberg Attorney-Harry A. Herbert, Jr. and Arsen Tashjian [57] ABSTRACT A bellows of SS-Nitinol metal within a liquid propellant storage tank in a liquid rocket is used to expel liquid propellant from the storage tank for use in the liquid rocket. The SS-Nitinol bellows is deformed, while at a temperature below the transition temperature of the 55-Nitinol, from the fully expel natural and normal position to the position necessary to permit filling of the storage tank with the liquid propellant. After the storage tank has been loaded with the liquid propellant, and when it becomes necessary to use the liquid propellant, the SS-Nitinol bellows is heated to a temperature above the'transition temperature of the SS-Nitinol. As a result, the 55- Nitinol bellows returns to the fully expel natural and normal position and, thereby, expels the liquid propellant from the storage tank for use in the liquid rocket.

2 Claims, 4 Drawing Figures Patented May 22, 1973 .IE IEJI How H770 M will?! BY [V I,

pry-NEW at or above its transition temperature. By definition, the transition temperature is that temperature at and above which the original natural and normal shape is restored. The transition temperature of SS-Nitinol may be made to vary, since it depends, in pertinent part, on the processing history of the particular 55- Nitinol. Stated another way, the transition temperature of a particular article of 55-Nitinol is known, although the transition temperature of different articles of SS-Nitinol may be different. Therefore, a specific transition temperature of the SS-Nitinol used in my method is not stated herein, although as previously stated the transition temperature of the particular SS-Nitinol used would be known. A discussion of the reasons for the shape recovery phenomenon of 55-Nitinol would serve no useful purpose herein and, therefore, will not be given, except to say that shape recovery of SS-Nitinol is the result of a transition in crystal structure.

My method of expelling liquid propellant from a storage tank on, and foruse by, a liquid rocket by the use of a SS-Nitinol bellows within the storage tank, wherein the bellows is used to expel the liquid propellant from the storage tank, comprises essentially six steps.

Firstly, I position the bellows to the position necessary to expel the liquid propellant from the storage tank. With regard to the wet expulsion of the liquid propellant, reference is made to FIG. 1 wherein are shown: storage tank with back end 21, and front end 22 with opening 23; SS-Nitinol" bellows 30, wholly within storage tank 20, with back end 31, and front end 32 with orifice -3-3 which fits into and extends through storage tank opening 23, and with the front end 32 of bellows 30 affixed to the internal surface of storage tank 20 near front end 22; bulkhead 40, wholly within storage tank 20 and affixed to the back end 31 of bellows 30; and liquid propellant 50, which is within, i.e., internal of, bellows 30. The position of the bellows 30 in FIG. 1 is the position necessary to expel, i.e., the fully expel position, liquid propellant 50 through orifice 33 from within bellows 30 which is within storage tank 20.

It is important to note that bellows 30, with bulkhead 40 affixed thereto, forms a liquid-impervious container which is closed at one end, i.e., back end 31, and is open at orifice 33 at the other end, i.e., front end 32.

With regard to the dry" expulsion of the liquid propellant, reference is made to FIG. 3, wherein are shown: storage tank 60 with back end 61 and, and front end 62 with orifice 63; SS-Nitinol bellows 70, wholly within storage tank 60, with back end 71 and front end 72, and with back end 71 affixed to the internal surface of storage tank 60 at back end 61; bulkhead 80, wholly within storage tank 60 and affixed to front end 72 of bellows 70; and liquid propellant 90 which is wholly outside of, i.e., external of, bellows 70. The position of bellows 70 in FIG. 3 is the position necessary to expel, i.e., the fully expel position, liquid propellant 90 through orifice 63 from storage tank 60.

It is important to note that bellows 70, with bulkhead 80 affixed to front end 72, and with back end 71 affixed to the internal surface of storage tank 60 at back end 61, forms a liquid-impervious unit which is closed at both ends.

This first step of my method is performed both as to the wet expulsion and as to the dry expulsion,

prior to launch of the rocket. In addition, during the performance of this step of my method, there is not any liquid propellant, respectively, in either bellows 30, FIG. 1, or storage tank 60, FIG. 3. Some liquid propellant is shown in FIGS. 1 and 3 as a matter of convenience, and in the interest of brevity, in explaining at a later time herein another step in my inventive method.

Then, I subject the bellows ofS5-Nitinol" (30, FIG. 1; 40, FIG. 3), while in the position and condition or shape shown in FIGS. 1 and 3, to a temperature above the transition temperature of the 5 S-Nitinol of which the bellows is made. This position and shape becomes the natural or normal position and shape of the bellows; and, the bellows will return to this position and shape, after deformation, whenever subjected again to a temperature above the transition Temperature of the 55- Nitinol of which the bellows is made. More specifically, it is important to note that the position and shape of bellows 30, as shown in FIG. 1, is now its normal or natural position and shape, i.e., neither expanded nor compressed, and that the bellows 30 normally remains in that position and shape. Similarly, the position and shape of bellows 70, as shown in FIG. 3, is also now its normal or natural position and shape, i.e., neither expanded nor compressed, and that the bellows normally remains in that position and shape. This step is also performed, both as to the wet expulsion and as to the dry expulsion, prior to launch of the rocket. In addition, during the performance of this step there is not any liquid propellant, respectively, either in bellows 30, FIG. 1, or storage tank 60, FIG. 3.

Then, while the SS-Nitinol bellows (30, FIG. I; 70, FIG. 3) is being subjected to a temperature below the transition temperature of the SS-Nitinol, I deform the SS-Nitinol bellows in a plastic sense, and not in an elastic sense, to the position necessary to permit the filling, i.e., the loading, of the storage tank with liquid propellant. With regard to the wet expulsion of the liquid propellant, reference is made to FIG. 2, wherein the same components as are shown in FIG. 1 have the same reference numerals in FIG. 2. With reference to FIG. 2, SS-Nitinol bellows 30 has been expanded, within storage tank 20, rearwardly beyond its normal expanded position, i.e., it has been deformed. Bellows 30, therefore, does not tend to return, i.e., contract to its normal position as shown in FIG. 1. Also shown in FIG. 2 is the relative rearward displacement of bulkhead 40. With regard to the dry expulsion of the liquid propellant, reference is made to FIG. 4, wherein the same components as are shown in FIG. 3 have the same reference numerals in FIG. 4. With reference to FIG. 4, SS-Nitinol bellows 70 has been compressed, within storage tank 60, rearwardly beyond its normal compressed or contracted position, i.e., it has been deformed. Bellows 70, therefore, does not tend to return, i. e., expand to its normal position as shown in FIG. 3. Also shown in FIG. 4 is the relative rearward displacement of bulkhead 80. This step is performed both as to the wet expulsion and as to the dry expulsion, prior to launch of the rocket. In addition, during the performance of this step of my method, there is not any liquid propellant, respectively, in either deformed bellows 30, FIG. 2, or storage tank 60, FIG. 4. Liquid propellant is shown in FIGS. 2 and 4 as a matter of convenience and, in the interest of brevity, in explaining at METHOD OF EXPELLING LIQUID PROPELLANT FROM A STORAGE TANK IN A LIQUID ROCKET BACKGROUND OF THE INVENTION This invention relates to a novel method of expelling a liquid propellant from a storage tank in a liquid rocket for use therein.

Bellows are presently used to expel liquid propellant from storage tanks in liquid rockets for use by the liquid rocket. These bellows are actuated, and the liquid propellant is expelled thereby, by air or some other gas, stored or generated aboard the liquid rocket, which is injected or otherwise introduced into the liquid propellant storage tank, causing a pressurized flow of the liquid propellant to the combustion chamber of the liquid rocket. The storage of gas requires gas storage bottles or the like, and generated gas requires gas generators, aboard the rocket. The gas storage bottles, and the gas generators, add weight and complexity to the rocket. The added weight results in an undesired geometric increase of the thrust required to propel the rocket. The added complexity undesirably increases the probability of the unreliability of the rocket as a whole. In addition, the gas storage bottles and the gas generators add to the cost of the rocket.

Therefore, there is a current critical need for a method of expelling liquid propellant from the storage tank without having to have, aboard the liquid rocket, gas generators or bottles or other containers of stored gas. I have invented such a method and have, thereby, significantly advanced the state-of-the-art.

SUMMARY OF THE INVENTION This invention pertains to a novel method of expelling liquid propellant from a storage tank aboard a liquid rocket for use by said rocket.

An object of this invention is to provide an efficient and reliable method of expelling liquid propellant from a storage tank aboard a liquid rocket.

Another object of this invention is to provide a simple and economical method of expelling liquid propellant from a storage tank aboard a liquid rocket, thereby eliminating the complexity and reducing the cost of one part of the present state-of-the-art propellant feed systems.

Still another object of this invention is to provide a novel method of expelling liquid propellant, from a storage tank aboard a liquid rocket, with a bellows but without the use of on-board gas storage bottles and gas generators, thereby resulting in significant saving in weight over the present stateof-the-art propellant feed systems.

These objects, and other equally important and related ones, of this invention will become readily apparent after a consideration of my inventive method and reference to the drawings.

DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are side elevation views, in crosssection and in simplified schematic form, of the relative position of the storage tank, the bellows, and the liquid propellant during different steps of my method, as it applies to wet expulsion of the liquid propellant; and,

FIGS. 3 and 4 are side elevation views, in crosssection and in simplified schematic form, of the relative position of the storage tank, the bellows, and the liquid propellant during different steps of my method, as it applies to dry" expulsion of the liquid propellant.

DESCRIPTION OF THE METHOD My inventive method can be better appreciated and understood if the following preliminary matters are noted and remembered.

Firstly, the term liquid propellant is intended, as a matter of simplicity, to be synonymous and interchangeable with, liquid fuel or liquid oxidizer. As is known, a liquid rocket uses both a liquid fuel and an oxidizer, in liquid form; and, a description of my method as it applies to the expulsion of the liquid fuel from the fuel storage tank and of the liquid oxidizer from the oxidizer storage tank would only be duplicitous and would serve no useful purpose. Therefore, my method will be described solely as it applies generically to the expulsion of a liquid propellant from a storage tank which is part of a liquid propellant feed system of and on a liquid rocket.

Secondly, although reference has been made, and will be made, of the use of my method in the liquid rocket art, it is obvious that this is but one specific application of my method, by way of illustration only, and is not intended to be a limitation. For example, my method may be used to expel the liquid oxidizer in, and for use by a hybrid rocket, i.e., one where the fuel is a solid. Additionally, my method may be used, or may be adapted for use, with regard to the expulsion of any liquid from any storage tank or other container.

Thirdly, the term expel and its derivatives is intended to mean to force out, to cause the flow, and the like.

Fourthly, the phraseology wet expulsion (or wet positive expulsion) and dry expulsion (or dry positive expulsion) will be discussed and more fully explained hereinafter. However, it is to be noted at this time that wet expulsion is with reference to the condition where the liquid propellant is stored within the bellows which is within the propellant storage tank, and that dry expulsion is with reference to the condition where the liquid propellant is stored external of the bellows, but within the propellant storage tank.

Fifthly, the term deformed when used with reference to the bellows is intended to mean a plastic, not merely an elastic, change in shape.

Sixthly, the term or name Nitinol is an artaccepted acronym (i.e., nickel-titanium, Naval Ordnance Laboratory) for a series of novel structural alloys of nickel and titanium which, as far as is known by the applicant, are disclosed and claimed in the U. S. Pat. to Buehler et al., No. 3,174,851, issued on Mar. 23, 1965. -Nitinol is the art-accepted designation of Niti- 1101 which contains 55 percent of nickel by weight and 45 percent of titanium by weight. SS-Nitinol is known as the metal with a memory in that it exhibits a unique mechanical memory effect by returning to its original natural and normal shape and dimensions after having been plastically deformed out of shape. By natural and normal shape and dimensions is meant the position and condition in which the article SS-Nitinol is set while being subjected to a temperature at or above the transition temperature. More specifically, if an article of SS-Nitinol is deformed while at a temperature below what is known as its transition temperature, it will return to its original natural and normal shape and dimensions if it is subjected to a temperature a later time herein another step of my inventive method.

Then while the bellows is deformed (30, FIG. 2; 70, FIG. 4) I fill, i.e., load the storage tank with liquid propellant. With regard to the wet expulsion of the liquid propellant and with reference toFIG. 2, I fill the deformed expanded bellows 30 which is wholly within storage tank 20 and occupies its entire interior with liquid propellant 50. I, therefore, in a loose linguistic sense and broadly speaking, fill the storage tank 20 with the liquid propellant 50. With regard to the dry expulsion of the liquid propellant, and with reference to FIG. 4, I fill storage tank 60 with liquid propellant 90. The filling of the deformed bellows 30, FIG. 2 (in storage tank 20, FIG. 2) and of storage tank 60, FIG. 4, is performed by conventional means through a suitable inlet, such as 33, FIG. 2, and 63, FIG. 4, prior to launch of the rocket. In essence, then, FIG. 2 shows the relative position of the components and of the liquid propellant during the fully loaded condition of wet expulsion. Likewise, FIG. 4 shows the relative position of the components and of the liquid propellant during the fully loaded condition of dry expulsion.

Then I subject the deformed 5S-Nitinol bellows (30, FIG. 2; 70, FIG. 4) to a temperature above the transition temperature of the SS-Nitinol. Because of the phenomenon and property of mechanical memory of SS-Nitinol, which has already been discussed, the deformed 55-Nitinol bellows (30, FIG. 2; 70, FIG. 4) returns to its natural or normal position and shape, i.e., the position it had, and the condition or shape it was in, prior to when the SS-Nitinol bellows was subjected to a temperature below the transition temperature of the 55-Nitinol. More specifically, and with reference to the wet expulsion of the liquid propellant deformed expanded bellows 30, FIG. 2, contracts and returns to its natural or normal position and shape shown in FIG. 1 and, thereby, expels liquid propellant 50, FIGS. 1 and 2, from bellows 30 and storage tank 20, FIGS. 1 and 2, through orifice 33, FIGS. 1 and 2. With reference to the dry expulsion of the liquid propellant, deformed compressed bellows 70, FIG. 4, expands and returns to its natural or normal position and shape shown in FIG. 3, and thereby expels liquid propellant 90, FIGS. 3 and 4 from storage tank 60, FIGS. 3 and 4, through orifice 63, FIGS. 3 and 4. This step is performed at launch time of the rocket. However, it may be adapted to be performed by known conventional means, such as a command signal from a ground-based station, while the rocket is already in flight. Additionally, it is to be understood, of course, that orifice 33, FIGS. 1 and 2 and orifice 63, FIGS. 2 and 4 are connected, respectively, to an appropriate liquid propellant feed system (not shown) of and on the liquid rocket, which system may include but is not limited to valves, regulators, delivery tubes and injectors which will insure the flow of the liquid propellant (50, FIG. 2; 90, FIG. 4) to the combustion chamber of the liquid rocket. Further, the heating of the SS-Nitinol" bellows to a temperatureabove the transition temperature of the SS-Nitinol" may be by any known conventional means, such as on-board electric resistance heating or hot gas drawn from the combustion of the liquid rocket propellants.

While there have been shown and described the fundamental features, and steps, of my inventive method, as applied to a method of expelling liquid propellant from a storage tank in a liquid propellant feed system of and on a liquid rocket, it is to be understood that various substitutions, omissions and adaptations of my inventive method may be made by those of ordinary skill in the art without departing from the spirit of the invention.

What is claimed is:

1. A method of expelling liquid propellant from a storage tank which is part of a liquid propellant feed system of, and on, a liquid rocket for use of the liquid propellant by the rocket, wherein a close-ended bellows of 55-Nitinol metal, which is wholly within the storage tank, is used to expel the liquid propellant, comprising the steps of:

a. positioning the bellows to the position necessary to expel the liquid propellant from the storage tank;

b. subjecting the bellows, while in the expel position, to a temperature above the transition temperature of the SS-Nitinol metal of which the bellows is made;

c. subjecting the bellows to a temperature below the transition temperature of the 55-Nitinol metal of which the bellows is made;

(I. deforming the bellows, while at a temperature below the transition temperature of the 55- Nitinol metal of which the bellows is made, to the position necessary to permit the loading of the storage tank with the liquid propellant;

e. loading the storage tank with the liquid propellant;

f. and, subjecting the deformed bellows to a temperature above the transition temperature of the 55- Nitinol metal of which the bellows is made; whereby the bellows of SS-Nitinol metal returns to the position necessary to expel the liquid propellant from the storage tank and the liquid propellant is, thereby, expelled from the storage tank for use by the liquid rocket.

2. A method of expelling liquid propellant from within a storage tank which is part of a liquid propellant feed system of, and on, a liquid rocket for use of the liquid propellant by the rocket, wherein a bellows of 55- Nitrinol metal, which is open at one end and which is wholly within the storage tank, is used to store and to expel the liquid propellant, comprising the steps of:

a. positioning the bellows to the position necessary to expel the liquid propellant from the bellows and from the storage tank;

b. subjecting the bellows, while in the expel position, to a temperature above the transition temperature of the SS-Nitinol metal of which the bellows is made;

c. subjecting the bellows to a temperature below the transition temperature of the SS-Nitinol metal of which the bellows is made;

d. deforming the bellows, while at a temperature below the transition temperature of the 55- Nitinol metal of which the bellows is made, to the position necessary to permit the loading of the bellows within the storage tank with the liquid propellant;

e. loading the deformed bellows within the storage tank with the liquid propellant;

f. and, subjecting the loaded, deformed bellows to a temperature above the transition temperature of the SS-Nitinol metal of which the bellows is made; whereby the bellows of SS-Nitinol metal returns to the position necessary to expel the liquid propellant from the bellows and from the storage tank, and the liquid propellant is, thereby expelled from the bellows and from the storage tank for use by the liquid rocket. 

2. A method of expelling liquid propellant from within a storage tank which is part of a liquid propellant feed system of, and on, a liquid rocket for use of the liquid propellant by the rocket, wherein a bellows of ''''55-Nitrinol'''' metal, which is open at one end and which is wholly within the storage tank, is used to store and to expel the liquid propellant, comprising the steps of: a. positioning the bellows to the position necessary to expel the liquid propellant from the bellows and from the storage tank; b. subjecting the bellows, while in the expel position, to a temperature above the transition temperature of the ''''55-Nitinol'''' metal of which the bellows is made; c. subjecting the bellows to a temperature below the transition temperature of the ''''55-Nitinol'''' metal of which the bellows is made; d. deforming the bellows, while at a temperature below the transition temperature of the ''''55-Nitinol'''' metal of which the bellows is made, to the position necessary to permit the loading of the bellows within the storage tank with the liquid propellant; e. loading the deformed bellows within the storage tank with the liquid propellant; f. and, subjecting the loaded, deformed bellows to a temperature above the transition temperature of the ''''55-Nitinol'''' metal of which the bellows is made; whereby the bellows of ''''55-Nitinol'''' metal returns to the position necessary to expel the liquid propellant from the bellows and from the storage tank, and the liquid propellant is, thereby expelled from the bellows and from the storage tank for use by the liquid rocket. 